In recent years, those having good wettability to a display surface as an adherend, and having adhesive strength proper for light peeling at the time of peeling off are required as a pressure-sensitive adhesive sheet for surface protection to be used for surface protection of display surfaces of electronic mobile appliances including smart phones as well as personal computers, televisions, and the like.
A pressure-sensitive adhesive sheet for surface protection (surface protective sheet) is peeled off after bonding and again bonded, and these operations are often repeated in many cases. Because of this, proper wettability is necessary and it is required that the sheet can be re-bonded while giving good appearance by manual bonding.
In such requests, silicone-based pressure-sensitive adhesives having high wettability have been used as pressure-sensitive adhesives for surface protection; however, they have a problem of high cost.
Further, awareness of environments has been considered to be important year by year, and extrication from dependence on petroleum is supposed to be an urgent issue, and it is highly expected to transfer to plant-derived materials without using petroleum resources as much as possible. In such a situation, a polyester-based pressure-sensitive adhesive using a dimer acid and a dimer diol derived from plants has been discussed (Patent Document 1), but also has a problem of high cost.
Therefore, in order to solve the above-mentioned problems, pressure-sensitive adhesive sheets for surface protection by using low cost acryl-based pressure-sensitive adhesives have been proposed (reference to Patent Documents 2 and 3).
However, in the case of using the acryl-based pressure-sensitive adhesives, a plasticizer is used and there occurs a problem of bleeding out of a plasticizer component and thus causing staining of an adherend after the acryl-based pressure-sensitive adhesives are bonded to a display surface as an adherend.